1. Field of the Invention
This invention relates to clutch type systems and in particular to a torque responsive actuation device for a belt driven power train arrangement as is commonly used on snowmobiles, and the like.
2. Prior Art
The present invention is in a driven clutch assembly or torque responsive actuation device that is a significant improvement over prior systems by an inclusion of cam follower bearings in place of slides for travel along a clutch helix or cam upright tracks that have radiused surfaces, which cam follower travel spreads pulley halves apart. The pulley opening is matched by closure of a drive clutch to where, based upon engine speed, the one clutch opens its pulley reducing the radius the belt traveling therearound senses as the other clutch closes its pulley increasing the pulley radius that the belt senses. The belt is thereby maintained tightly within the pulleys with changes in applied torque producing changes of the clutch pulley radiuses providing for shifting.
To decrease friction and diminish binding between which cam follower bearings and the upright tracks whereon they travel, the tracks are each radiused to present a convex surface therealong that the individual bearing rollers will each travel along, the curved surface providing for centering the roller in the track as the cam follower bearing roller travels therealong. Which center roller travel provides for a very smooth clutch upshift and backshift relative movement and minimizes a roller getting hung up on a track edge as could cause the clutch to lock up. The clutch assembly of the present invention therefore operates more reliably with less component wear than earlier clutch arrangements and an example of an earlier driven clutch arrangement that the present invention improves upon is shown in FIGS. 1 and 1A, that show a driven clutch system known as a Reverse Cam Driven Clutch, manufactured by Arctco, Inc.